Sodium Carbonate → 3-(2-Chloro-4-pyrimidinyl)-1-(phenylsulfonyl)-1H-indole

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Reaction Steps

A solution of 2,4-dichloropyrimidine (2.42 g, 16 mmol), 1-(phenylsulfonyl)-1H-indol-3-ylboronic acid (3.89 g, 13 mmol) and sodium carbonate (5.03 g, 47 mmol) in acetonitrile/water (2:1, 60 mL) was degassed with argon, then tetrakis(triphenylphosphine)palladium (300 mg, 1.6 mol) was added. The resulting mixture was heated to reflux for 2 h while a white suspension formed. The precipitate was cooled and filtered through a CELITE™/Silica gel plug. The filter cake was washed with EtOAc, the organic layer separated, washed with brine, dried over Na2SO4, filtered, and evaporated under reduced pressure. The residue was recrystallized from EtOAc/hexanes to give 1-benzenesulfonyl-3-(2-chloro-pyrimidin-4-yl)-1H-indole as a light-pink solid. The solid filtrate from the reaction mixture was dissolved in DCM, dried over Na2SO4, filtered, and combined with the previous batch of product. The collected solids were dissolved in DCM, the solvent was evaporated under reduced pressure and EtOAc was added to form a suspension, the product was filtered and washed with hexanes, to give 1-benzenesulfonyl-3-(2-chloro-pyrimidin-4-yl)-1H-indole (2.0 g, 33% yield) as a light-pink solid. An additional 0.45 g of product was obtained from the mother liquors.

Provenance & Evidence